THERMOCHIMICA ACTA
·
2013
·
IF 1.989
Haisu Gao,Liping Chen,Wanghua Chen,Shilong Bao
The thermal stability of β-artemether under dynamic, isothermal and adiabatic conditions were investigated by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. The dynamic DSC measurements at various heating rates (1, 2, 4 and 8 °C min −1 ) displayed that β-artemether experienced polymorph transformation in the melting process. According to the isothermal DSC results at different temperatures 86, 88, 90 and 92 °C, β-artemether decomposed after the completion of the melting and the polymorph transformation, and the thermal decomposition of β-artemether is hazardous for its characteristic of autocatalytic decomposition. The kinetics analysis dynamically and isothermally described by Friedman method indicated the thermal decomposition of β-artemether did not comply with a single mechanism. The ARC results showed that the pressure increased with the increase of temperature, and indicated obvious linear relationship. Based on the ARC data, the value of SADT of β-artemether in 50 kg package was obtained.
研究领域:
药学
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化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Daoyuan Zu,Haoran Song,Changping Li,Yuwei Wang,Rong Du,Rui Zhou,Wei Zhang,Shiting Pan,Yang Cai,Yongming Shen,Zhifeng Yang
Self-catalyzed decomplexation of Cu-ethylene diamine tetraacetic acid complex (Cu-EDTA) and recovery of Cu without addition of extraneous transition metals were achieved in Ti 3 C 2 T x MXene/peroxymonosulfate (Ti 3 C 2 T x /PMS) process. Free radical quenching experiments and electron spin resonance (ESR) measurements demonstrated that both hydroxyl radical (HO • ) and sulfate radical (SO 4 •- ) contributed to the degradation of Cu-EDTA. Activation of PMS by Ti 3 C 2 T x initiated Cu-EDTA decomplexation and released free Cu ions . Then, the formation of Ti-O-Cu bonds between Cu ions and Ti 3 C 2 T x accelerated the electron transfer from Ti 3 C 2 T x to Cu(Ⅱ) and triggered Cu(Ⅱ)/Cu(Ⅰ) cycle, which further enhanced PMS activation and led to the self-catalyzed decomplexation of Cu-EDTA. Simultaneous recovery of Cu was achieved due to the excellent absorption performance of negative charged Ti 3 C 2 T x towards Cu ions. This study revealed the self-catalyzed decomplexation mechanism of Cu-EDTA in the Ti 3 C 2 T x /PMS process and provided a feasible strategy for heavy metal complexes treatment.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 23
·5668
·
IF 4.2
Dengxun Ren,Zexu Fan,Jiaqu Zhang,Yi Xu,Xianzhong Tang,Mingzhen Xu
To study the properties of cyclotriphosphazene (CTP)-containing phthalonitriles, a branched phthalonitrile containing CTP (CTP–PN) with self-catalytic behavior was designed and synthesized. The structure of CTP–PN was characterized by FT–IR (Fourier transform infrared spectroscopy), MS (mass spectroscopy), 1 H–NMR (proton nuclear magnetic resonance spectroscopy), and 13 C–NMR (carbon nuclear magnetic resonance spectroscopy). Then, the curing reaction of CTP–PN was studied using DSC (differential scanning calorimetry) and DRA (dynamic rheological analysis). The results show that the curing reaction of CTP–PN is initiated at 200 °C. Additionally, the change in the viscosity of CTP–PN as a function of the temperature was investigated. After curing at different temperatures, the generated structures were characterized by FT–IR. The fracture morphology and thermomechanical properties of cured CTP–PN were scanned and studied using SEM (scanning electron microscopy) and TMA (thermomechanical analysis), respectively. The results demonstrate that CTP–PN exhibits a smooth fracture surface and possesses a relatively low CTE (coefficient of linear thermal expansion) of approximately 25 ppm/°C at 285 °C. A T d5% (temperature at which 5% weight loss occurs) of as high as 405 °C can be obtained for cured CTP–PN, and its char yield at 800 °C exceeds 70% in N 2 . FT–IR and XPS (X-ray photoelectron spectroscopy) were used to study the thermal decomposition of cured CTP–PN, indicating that it remains stable below 350 °C. With an increasing temperature, there is decomposition first of CTP and P–NH–Ph and C–O–C bonds (>350 °C) and then nitrogen-containing aromatic heterocycles (>500 °C), ultimately resulting in the formation of P-containing residual char.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Tao He,Xiaoben Zhao,Shuainan Wang,Song He,Ye Li
This research delves into the combined impact of employing sodium lignosulfonate as a feedstock, along with its inherent self-activating property and co-activation with KOH, in the preparation of activated carbon. Studies suggest that the natural activator, Na, aids in the internal creation of pores, thereby decreasing the reliance on KOH. The resulting activated carbon boasts a substantial specific surface area of 3362 m²/g, a significant micropore volume of 1.3435 cm³ /g, and considerable doping levels of nitrogen (1.09 %) and sulfur (2.46 %). Analysis of CO 2 adsorption indicates that the adsorption heat escalates with the quantity of CO 2 adsorbed, highlighting the pivotal role of micropores in this process. Monte Carlo simulations further demonstrate that narrowing the pore size range boosts CO 2 adsorption uptake. Nevertheless, as the temperature rises, the ability of micropores to capture carbon dioxide decreases, as shown by the increasing difference in adsorption capacity from 0 °C to 25 °C.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Dongfei Zhang,Ao Wang,Wenkai Liu,Ao Zhen,Jiehua Li,Feng Luo,Xianglong Han,Zhen Li,Hong Tan
The reported dynamic covalent bonds (DCBs) exhibit certain drawbacks, including sluggish reaction rates and high dissociation temperatures, which impede the reusability of DCBs cross-linked polymers. Herein, we develop a kind of imidazole-urea bond (IUBs) through the rapid self-catalytic reaction between imidazole and isocyanate without additional catalysts. The IUBs are found to be highly reversible via a thermally dissociative mechanism while also demonstrating an irreversible exchange with amines. Then, histamine (1H-imidazole-4-ethanamine) is first employed as a chain extender to construct IUBs in the synthesis of novel imidazole-based cross-linked polyurethane-ureas (IMCPU). The IMCPU can undergo multiple recyclings of melt processing and be aminolyzed even at room temperature. Given the wide availability of the commodity histamine, IMCPU exhibits great potential for broad applications in the fields of dynamic materials.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Junfeng Zhao,Yiqing Liu,Qun Wang,Yongsheng Fu,Xiaohui Lu,Xiaofeng Bai
In this study, the effect of phosphate, Fe(III), Fe(II), and reductive substances (i.e., Mn 2+ and SO 3 2− ) on diclofenac (DCF) oxidation and its degradation mechanism by Ferrate (Fe(VI)) were investigated. The removal rate of DCF in reaction solution at pH 9.0 adjusted by NaOH (67.36%) was higher than that by phosphate buffer (14.87%) because of the complexation of phosphate with Fe(III) and/or Fe(II) restraining the self-catalysis of Fe(VI). Fe(III) or Fe(II) could significantly catalyze Fe(VI) to generate more intermediates (i.e., Fe(V) and Fe(IV)), whose oxidation capacity was magnitude stronger than that of Fe(VI), leading to the improvement of DCF degradation, besides, the presence of reductive substances, e.g., Mn 2+ and SO 3 2− , could also increase the self-catalysis of Fe(VI), enhancing the removal of DCF, which will be further verified in follow-up studies. Seven oxidation products (OPs) were detected using a quadrupole-time of flight-mass spectrometer coupled with an ultra performance liquid chromatograph (LC-QTOF/MS). Based on these identified OPs, the potential degradation mechanism of DCF by Fe(VI) was proposed showing six reaction pathways, including hydroxylation, decarboxylation, C N bond cleavage, dehydrogenation, formylation, and dechlorination-hydroxylation. This study suggests that Fe(VI) can effectively oxidize and degrade DCF.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
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2020
·
IF 3.421
Xiaomei Yang,Beibei Wang,Tianliang Lu,Lipeng Zhou
Depolymerization of the cellulose component of lignocellulose to glucose is one of the most vital steps for lignocellulose biorefineries. In this report, a self–catalyzed hydrolysis strategy was successfully applied for the selective depolymerization of the cellulose component of wheat straw. After removal of most part of the hemicellulose component by high-pressure CO2–H2O in the presence of acetic acid, the biomass was oxidized by molecular oxygen to convert partial hydroxymethyl groups on glucose units of cellulose to carboxyl groups. The generated acid sites act as the catalytic active centers for the following depolymerization of the cellulose component. As high as 41.6% yield of glucose was obtained in water at 170 °C for 6 h without additional catalyst. Additionally, a high ratio of biomass to water (10 wt %) was suitable for this method.
研究领域:
生物化学
·
可再生资源工程
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2023
·
IF 3.4
Shichun Weng,Wei Feng,Wenqian Wu,Zichao Guo,Liping Chen,Wanghua Chen
Nitrophenols and corresponding sodium nitrophenolates are the main side products in the production of mononitrobenzene (MNB). These side products are hazardous due to their thermal instability nature. In this article, the thermal decomposition behaviors of nitrophenols and sodium nitrophenolates were first characterized by differential scanning calorimeter and accelerating rate calorimetry techniques. Then, the influence of phenol and sodium phenolate on the thermal decomposition of MNB was studied to clarify the effect of phenolic hydroxyl groups on the thermal stability of nitrophenols. It was found that compared to nitrophenols, the exothermic peaks of sodium nitrophenolates were more intense and presented strongly autocatalytic features. Sodium phenolate could significantly decrease the decomposition temperature of MNB. Aniline was detected as the unique product in the decomposition processes of pure MNB and MNB/sodium phenolate mixtures, and the nitrosobenzene was verified as the intermediate product. It was experimentally proven that sodium phenolate could catalyze the decomposition of nitrosobenzene (the decomposition intermediate of MNB). The violent decomposition of sodium nitrophenols was caused by the intermolecular catalysis effect of phenoxy groups.
研究领域:
化学工程
·
安全科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Donghui Wang,Jiakang Xu,Jinyan Tan,Jinlong Yang,Shuxue Zhou
Amphiphilic coatings, especially those containing zwitterionic groups, are promising as antifouling coatings. Nevertheless, zwitterion based amphiphilic coatings suffer from poor miscibility between hydrophobic and hydrophilic ingredients. Zwitterionic precursors are good candidates to circumvent this issue, but acid or alkaline water must be used in-situ for the zwitterionic group to be self-generated. The in-situ feature restricts its applicability. The objective of this work focuses on developing a new zwitterionic precursor for easy fabrication of zwitterionic groups containing amphiphilic antifouling coatings. This precursor, i.e., triisopropylsilyl 2-methyl-3-((3-(triethoxysilyl)propyl) amino) propanoate (TMAP), was facile synthesized by one step of aza -Michael addition of (3-aminopropyl) triethoxysilane (APS) and triisopropylsilyl methacrylate. Then further blended with hydroxyl-terminated PDMS (HO-PDMS). The curing behavior, morphology, wetting behavior and the antifouling performance both in lab and field were thoroughly examined for coatings with various amounts of TMAP. It was interesting to find that TMAP could not only be hydrolyzed in-situ into a zwitterionic group via a self-catalytic effect during the curing process, but it also efficiently crosslinked the HO-PDMS under ambient conditions. In contrast to APS, TMAP was also more compatible with HO-PDMS and endowed the coating with relatively homogeneous and a smooth surface after prolonged submersion in artificial seawater. The TMAP-based amphiphilic coatings efficiently mitigated the microfouling in both the laboratory assay and the natural field condition in contrast with common silicone elastomer . Notably, excellent resistance for the macrofouler of the mussel was observed for these coatings, especially for 50 wt% TMAP containing coating with zero settlement.
研究领域:
材料科学
·
海洋生物学
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2018
·Vol. 8
·期 9
·664
·
IF 3.504
Hui Wang,Xi Zhang,Yan Wang,Guixiang Quan,Xiangyun Han,Jinlong Yan
Magnetic nitrogen-doped porous carbon (MNPC) has been prepared via self-catalytic pyrolysis of bimetallic metal-organic frameworks (MOFs). The as-obtained MNPC showed favorable features for antibiotics adsorption such as high specific surface area (871 m2g−1), high pore volume (0.75 cm3g−1), porous structure, good graphitization degree, and rich N-doping. Moreover, the MNPC has magnetic properties due to the Co species, which is embedded with a high dispersion, so the absorbent can be easily separated. Based on the above excellent characteristics, the MNPC was used as the absorbent for norfloxacin (NOR) removal. The experimental maximum NOR adsorption capacity of MNPC was 55.12 mg g−1at 298.15 K and a pH of 6.0 with an initial NOR concentration of 50 mg L−1. The data analysis of the kinetics revealed that the experimental data of NOR uptakes versus time agreed with the pseudo-second order model. The isotherm data analysis revealed the favorable application of the Freundlich model. Based on the adsorption results over a wide range of conditions, the dominant adsorption mechanisms were found to be pore-filling, electrostatic interaction, and the H-bond.Keywords:self-catalytic pyrolysis;porous carbon;metal–organic frameworks;antibiotics;adsorption
研究领域:
材料科学
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环境科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2022
·
IF 1.73
Sarah Soudjrari,Mehdi Derradji,Bouchra Amri,Khawla Djaber,Oussama Mehelli,Sana Tazibet,Slimane Abdous,Noureddine Ramdani,Wenbin Liu,Azzedine Khadraoui
Benzoxazine containing phthalonitrile, as one of the most advanced high performance thermosetting resin, has gained a lot of attention in the last decades. Indeed, the combination of the thermally activated ring-opening polymerization of the benzoxazine and the cyano addition reaction of the phthalonitrile allows the development of robust polymeric networks. Following this path, a renewable natural resource, vanillin, was used to develop a new benzoxazine containing phthalonitrile thermosetting system. The newly developed monomers present the advantage of a simple synthesis process along with an autocatalytic polymerization mechanism. The molecular structures of the synthesized monomers were characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy . Thermal properties were also characterized by differential scanning calorimetry and thermogravimetric analysis . Typically, the newly developed monomers showed excellent thermal stability with starting decomposition temperatures over 496.4°C with a char yield at 800°C of about 80.7%. The thermomechanical properties were investigated by dynamic mechanical analyzer and the fractured surfaces were studied by scanning electron microscopy Globally, the newly developed partially bio polymer showed outstanding thermal resistance along with excellent thermomechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2024
·
IF 1.8
Abdelwahed Berrouane,Mehdi Derradji,Karim Khiari,Oussama Mehelli,Slimane Abdous,Abdelmalek Habes,Wenbin Liu,Azzedine Khadraoui
Quercetin (Q), one of the most abundant molecules in nature, remains relatively unexplored in the realm of bio-based thermosets. In line with the pursuit of sustainability, we report the successful synthesis of a novel bio-based phthalonitrile (PN) monomer (Q-Ph) using Q. The synthesis involved a nitro displacement reaction with 4-nitrophthalonitrile (4-NPN). Confirmation of the monomer’s structure utilized hydrogen and carbon nuclear magnetic resonances (1H and 13C NMR), Fourier transform infrared spectra (FTIR), and elemental analysis. Curing characteristics were examined by differential scanning calorimetry (DSC), and polymerization was analyzed using FTIR. The resulting monomers showed a wide processing window and low melt viscosity via rheological analysis. Thermal and thermomechanical properties were assessed using dynamic mechanical analyzer (DMA) and thermogravimetric analysis (TGA), revealing lower curing and polymerization temperatures compared to petroleum-based counterparts. The synthesized resin achieved a high Tg exceeding 400°C, a char yield of 79% at 1000°C, and T5% and T10% values of 564 and 660°C, respectively. The Q-Ph polymer demonstrated superior performance, with evidence of an autocatalytic curing mechanism. These results highlight quercetin as a promising petrochemical replacement for the preparation of self-curable PN thermosets, especially for high-performance applications.
研究领域:
材料科学
·
有机化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）